1. Field of the Invention
The invention relates to an adjustable two-way valve device for a combustion engine with a housing in which a first and a second outlet or inlet channel, a third outlet or inlet channel, and at least one valve element are arranged, whereby the at least one valve element is movable via a control unit such that a fluid connection can be produced at will between the first or the second outlet or inlet channel and the third outlet or inlet channel.
2. Background Art
Such two-way valve devices are known for example as combined exhaust gas recirculation and bypass valve devices in which two valve elements are activated translationally via a continuously adjustable control unit in order to reduce the emissions of a combustion engine in that in the warm-up phase the exhaust gas is conducted via the bypass channel and after heating of a catalyst, the exhaust gas is conducted via the EGR cooler of the combustion engine.
Accordingly, in DE 100 25 877 an exhaust gas recirculation system with a valve device is described, which valve device features one exhaust gas inlet and two exhaust gas outlets, whereby one of the exhaust gas outlets leads to a cooler and the other exhaust gas outlet is connected fluidly to a bypass channel that bypasses the cooler. In a housing between the exhaust gas inlet and the two exhaust gas outlets respectively a valve seat is arranged, which valve seats are governed respectively by a disk-shaped valve element. The valve elements are arranged on a valve rod that is movable translationally via a control unit, whereby the first valve element is fixed on a first valve rod and the second valve element, which is arranged closer to the control unit, is arranged immovably on a second tubular valve rod surrounding the first valve rod. The control unit is embodied so that two springs are arranged in the control unit, via which the two valve disks are pressed onto their valve seats in a tensioned position. The inner and outer valve rods are arranged so that they can be displaced with respect to one another, so that the pneumatic or electromotive control unit is embodied such that depending on the direction of movement, only one of the valve rods and thus also only one of the two valve elements is lifted from the corresponding valve seat.
Moreover in DE 198 12 702 A1, a valve arrangement for controlling a recirculated exhaust gas stream is described, whereby the latter is arranged downstream of a bypass channel and an exhaust gas cooler, so that this valve arrangement features two inlets and one outlet. The two valve elements arranged on the valve rod and each corresponding to a valve seat are respectively pressed onto the valve seat via two helical springs arranged in the channel. Each of the two valve elements features a hole in the middle through which the joint valve rod extends at least partly. Two coils are embodied on the valve rod, via which the valve elements can respectively be activated individually in the direction of opening against the spring force via the coil when the valve rod is activated, whereby the respective other valve element is to slide on the valve rod, since it is pressed onto the valve seat by the spring force.
Two-way valve devices in other fields of application are likewise known, whereby these are controlled electromagnetically as a rule. For example corresponding holes are arranged in the movable armature of the electromagnetic valves, which correspond to inlets or outlets embodied in the housing. These valves are usually embodied so that exactly two or three different positions of the armature can be controlled with respect to one another to connect the different paths. As a rule these are not continuously adjustable and for example are not suitable for regulated exhaust gas recirculation via a cooler or a bypass, since the movable armature situated in the stream would be too sensitive to soiling and sufficient flow cross-sections are not ensured in such valves.
Moreover from DE 101 01 412 A1 an exhaust gas recirculation device in the form of a rotary valve for a combustion engine is known. With this rotary valve, a disk-shaped switching element is rotated via a control unit. The switching element features control openings that correspond to passage openings in a valve plate, whereby these passage openings respectively form one end of individual channels leading to the air-intake channel system. However, such a valve cannot be used as a two-way valve device, since the outlet channels cannot be opened or closed individually, but always jointly and simultaneously, so that an identical mass flow is made available to each outlet channel.
In the known embodiments of two-way valve devices, the disadvantages of high cost and a large number of components are evident. It is very expensive to embody the control units with two meshing valve rods. Moreover there is a high sensitivity to soiling in embodiments with springs arranged in the channel and valve elements sliding on the valve rod, since rust deposits may form on the valve rod, as a result of which problem-free functioning is no longer ensured. In addition, the expense of production and assembly is very high due to the large number of components.